Method and system for synthetic jet cooling

ABSTRACT

A method and system for cooling a component are provided. The synthetic jet cooling system includes a plurality of synthetic jet assemblies configured to be positioned adjacent to a component that generates excess heat. Each of the plurality of synthetic jet assemblies includes a driver configured to excite a respective one of the plurality of synthetic jet assemblies at a varying frequency.

BACKGROUND OF THE INVENTION

The field of the invention relates generally to component coolingsystems, and more specifically, to a system and method of coolingcomponents using synthetic jets.

At least some known synthetic jet cooling systems produce unacceptablyhigh noise levels at a tone that is irritating to persons in the areawhen the synthetic jets are driven sufficiently strongly to produce theneeded airflow. By driving any one individual synthetic jet at aparticular frequency for only a short time, the time-weighted dB levelat any particular frequency is lowered. Since the intended usage for thesynthetic jet cooling method is primarily avionics, excessiveactively-cooled operating noise levels are always a customer and userconcern, and may preclude use of synthetic jet cooling method in someapplications.

Prior attempts at reducing the noise involved reducing the synthetic jetdrive level and alternating the phasing of the jet modules in an arrayof synthetic jets. However, neither was acceptable, as reducing thedrive level reduced the desired air flow; alternating the phasing didnot produce a significant change.

BRIEF DESCRIPTION OF THE INVENTION

In one embodiment, a synthetic jet cooling system includes a pluralityof synthetic jet assemblies configured to be positioned adjacent to acomponent that generates excess heat. Each of the plurality of syntheticjet assemblies includes a driver configured to excite a respective oneof the plurality of synthetic jet assemblies at a varying frequency.

In another embodiment, a method of cooling a component includespositioning a plurality of synthetic jet assemblies adjacent a componentthat generates excess heat and separately driving each of the pluralityof synthetic jet assemblies at a frequency that varies between a firstfrequency limit and a second frequency limit.

In yet another embodiment, an electronic component system includes acomponent enclosure including a plurality of sidewalls defining avolume, a heat generating component positioned within the volume, and asynthetic jet cooling system positioned adjacent the componentenclosure. The synthetic jet cooling system includes a plurality ofsynthetic jet assemblies communicatively coupled to a respective driverconfigured to excite the synthetic jet assembly at a varying frequency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-2 show exemplary embodiments of the method and system describedherein.

FIG. 1 is a perspective view of a synthetic jet cooling system inaccordance with an exemplary embodiment of the present invention; and

FIG. 2 is a flow diagram of a method 200 of cooling a component inaccordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description illustrates embodiments of theinvention by way of example and not by way of limitation. It iscontemplated that the invention has general application to reducing aperceived noise generated by equipment operating in industrial,commercial, and residential applications.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralelements or steps, unless such exclusion is explicitly recited.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features.

FIG. 1 is a perspective view of a synthetic jet cooling system 100 inaccordance with an exemplary embodiment of the present invention. In theexemplary embodiment, a plurality of synthetic jet assemblies 102 areconfigured to be positioned adjacent a component 104 that generatesexcess heat, such as, but not limited to, an aircraft avionicsenclosure. Each of the plurality of synthetic jet assemblies 102includes at least one synthetic jet ejector 106 that includes a jet port108. Jet port 108 is aligned at least one of perpendicularly,parallelly, and obliquely with a surface 110 of component 104. Each ofthe plurality of synthetic jet assemblies 102 includes a controller 112communicatively coupled to plurality of synthetic jet assemblies 102. Inthe exemplary embodiment, controller 112 includes a processor 114programmed to control at least one driver 116 configured to excite arespective one of the plurality of synthetic jet assemblies 102 at avarying frequency. In the exemplary embodiment, driver 116 iscommunicatively coupled to a piezoelectric actuator 118 associated witha respective synthetic jet assembly 102. Piezoelectric actuator 118 isconfigured to vibrate such that a flow of fluid is generated, whichexits the synthetic jet assembly 102 in a predetermined directionthrough jet port 108. Driver 116 may be programmable using softwareand/or firmware to excite synthetic jet assembly 102 or may excitesynthetic jet assembly 102 in a fixed manner. Driver 116 may excitesynthetic jet assembly 102 at least one of frequency that variesrandomly, varies pseudo-randomly, varies linearly, and a combination ofthe above. Driver 116 may excite synthetic jet assembly 102 at afrequency that varies between a first limit and second limit, the firstlimit being greater than the second limit.

In one embodiment, component 104 comprises a synthetic jet assemblyhousing (not shown for clarity) formed integrally with the surface ofthe component. In various embodiments, synthetic jet assembly 102comprises a single housing couplable to surface 110 of component 104.

Synthetic jet assemblies 102 are arranged in arrays, as required, tocool electronic equipment, such as, but not limited to, component 104,in lieu of traditional cooling fans, or to augment cooling by naturalconvection of electronic equipment. Electronic circuits, such as, butnot limited to, driver 116 are connected to drive each synthetic jetseparately in a predetermined frequency distribution, over the frequencyrange allowable and useable for the synthetic jet assemblies 102. Thisreduces the human perceived sound level, and reduces the annoyancefactor of the current method.

FIG. 2 is a flow diagram of a method 200 of cooling a component inaccordance with an exemplary embodiment of the present invention. In theexemplary embodiment, method 200 includes positioning 202 a plurality ofsynthetic jet assemblies adjacent a component that generates excess heatand separately driving 204 each of the plurality of synthetic jetassemblies at a frequency that varies between a first frequency limitand a second frequency limit.

The term processor, as used herein, refers to central processing units,microprocessors, microcontrollers, reduced instruction set circuits(RISC), application specific integrated circuits (ASIC), logic circuits,and any other circuit or processor capable of executing the functionsdescribed herein.

As used herein, the terms “software” and “firmware” are interchangeable,and include any computer program stored in memory for execution byprocessor 114, including RAM memory, ROM memory, EPROM memory, EEPROMmemory, and non-volatile RAM (NVRAM) memory. The above memory types areexemplary only, and are thus not limiting as to the types of memoryusable for storage of a computer program.

As will be appreciated based on the foregoing specification, theabove-described embodiments of the disclosure may be implemented usingcomputer programming or engineering techniques including computersoftware, firmware, hardware or any combination or subset thereof,wherein the technical effect is controlling the excitation of aplurality synthetic jet assemblies operating together to cool anelectronic component. The excitation is controlled to operate thesynthetic jet assemblies at different pseudo-random frequencies, whichwhen combined, produce a perceived noise that is less harsh to a user.Any such resulting program, having computer-readable code means, may beembodied or provided within one or more computer-readable media, therebymaking a computer program product, i.e., an article of manufacture,according to the discussed embodiments of the disclosure. The computerreadable media may be, for example, but is not limited to, a fixed(hard) drive, diskette, optical disk, magnetic tape, semiconductormemory such as read-only memory (ROM), and/or any transmitting/receivingmedium such as the Internet or other communication network or link. Thearticle of manufacture containing the computer code may be made and/orused by executing the code directly from one medium, by copying the codefrom one medium to another medium, or by transmitting the code over anetwork.

The above-described embodiments of a method and system of coolingcomponents provides a cost-effective and reliable means for reducing theperceived noise produced by a plurality of synthetic jet air movers.More specifically, the method and system described herein facilitatereducing the perceived noise by driving the synthetic jets at varyingpseudo-random distributed frequencies. As a result, the method andsystem described herein facilitate cooling electronic components in acost-effective and reliable manner.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

1. A synthetic jet cooling system comprising a plurality of syntheticjet assemblies configured to be positioned adjacent a component thatgenerates excess heat, each of the plurality of synthetic jet assembliescomprising a driver configured to excite a respective one of theplurality of synthetic jet assemblies at a varying frequency.
 2. Asynthetic jet cooling system in accordance with claim 1, wherein each ofthe plurality of synthetic jet assemblies includes at least onesynthetic jet ejector comprising a piezoelectric actuator, said actuatorconfigured to vibrate such that a flow of fluid is generated.
 3. Asynthetic jet cooling system in accordance with claim 1, wherein saiddriver is configured to excite a respective one of the plurality ofsynthetic jet assemblies at a frequency that varies randomly.
 4. Asynthetic jet cooling system in accordance with claim 1, wherein saiddriver is configured to excite a respective one of the plurality ofsynthetic jet assemblies at a frequency that varies pseudo-randomly. 5.A synthetic jet cooling system in accordance with claim 1, wherein saiddriver is configured to excite a respective one of the plurality ofsynthetic jet assemblies at a frequency that varies linearly
 6. Asynthetic jet cooling system in accordance with claim 1, wherein saiddriver is configured to excite a respective one of the plurality ofsynthetic jet assemblies at a frequency that varies between a firstlimit and second limit, the first limit being greater than the secondlimit.
 7. A synthetic jet cooling system in accordance with claim 1,wherein each of the plurality of synthetic jet assemblies includes atleast one synthetic jet ejector comprising a jet port, said jet portaligned at least one of perpendicularly, parallelly, and obliquely witha surface of the component.
 8. A synthetic jet cooling system inaccordance with claim 1, wherein said component comprises a syntheticjet assembly housing formed integrally with the surface of thecomponent.
 9. A synthetic jet cooling system in accordance with claim 1,wherein said synthetic jet assembly comprises a plurality of syntheticjet ejectors enclosed in a single housing.
 10. A synthetic jet coolingsystem in accordance with claim 1, wherein said synthetic jet assemblycomprises a single housing couplable to the surface of the component.11. A method of cooling a component, said method comprising: positioninga plurality of synthetic jet assemblies adjacent a component thatgenerates excess heat; and separately driving each of the plurality ofsynthetic jet assemblies at a frequency that varies between a firstfrequency limit and a second frequency limit.
 12. A method in accordancewith claim 11 wherein separately driving each of the plurality ofsynthetic jet assemblies comprises separately driving each of theplurality of synthetic jet assemblies at a frequency that varies overtime.
 13. A method in accordance with claim 11 wherein separatelydriving each of the plurality of synthetic jet assemblies comprisesseparately driving each of the plurality of synthetic jet assemblies ata frequency that varies randomly.
 14. A method in accordance with claim11 wherein separately driving each of the plurality of synthetic jetassemblies comprises separately driving each of the plurality ofsynthetic jet assemblies at a frequency that varies pseudo-randomly suchthat a first audio noise generated by each of the plurality of syntheticjet assemblies is combined to a second audio noise, the second audionoise being perceived by a user as less annoying then the first audionoise.
 15. A method in accordance with claim 11 wherein separatelydriving each of the plurality of synthetic jet assemblies comprises:communicatively coupling a piezoelectric driver to a respective one ofthe plurality of synthetic jet assemblies; generating an electricalsignal in each of the piezoelectric drivers that is different from theelectrical signals generated in the other piezoelectric drivers; andtransmitting the generated electrical signals to the respectivesynthetic jet assemblies such that each of the plurality of syntheticjet assemblies is excited at a different frequency.
 16. An electroniccomponent system comprising: a component enclosure comprising aplurality of sidewalls defining a volume; a heat generating componentpositioned within the volume; and a synthetic jet cooling systempositioned adjacent the component enclosure, the synthetic jet coolingsystem comprising a plurality of synthetic jet assembliescommunicatively coupled to a respective driver configured to excite thesynthetic jet assembly at a varying frequency.
 17. A synthetic jetcooling system in accordance with claim 16, wherein each of theplurality of synthetic jet assemblies includes at least one syntheticjet ejector comprising a piezoelectric actuator, said actuatorconfigured to vibrate such that a flow of fluid is generated.
 18. Asynthetic jet cooling system in accordance with claim 16, wherein saiddriver is configured to excite a respective one of the plurality ofsynthetic jet assemblies at a frequency that varies randomly.
 19. Asynthetic jet cooling system in accordance with claim 16, wherein saiddriver is configured to excite a respective one of the plurality ofsynthetic jet assemblies at a frequency that varies pseudo-randomly. 20.A synthetic jet cooling system in accordance with claim 16, wherein saiddriver is configured to excite a respective one of the plurality ofsynthetic jet assemblies at a frequency that varies between a firstlimit and second limit, the first limit being greater than the secondlimit.